An electric car such as a direct current electric car normally collects direct current power from an overhead power line through a pantograph or from a third rail through a collector shoe and runs thereon. Each of the overhead power line or the third rail is composed of a plurality of sections separated from one another. Power is normally supplied from an electric power substation to each of the sections. Because of an abnormality of a power source facility, an abnormality of a car, a work on an overhead power line, or the like, there is the case where power supply is stopped in a section (hereinafter referred to as a power failure section). While the car goes through the power failure section in a regenerative braking state, an increase in overhead power line voltage or a ground fault occurs depending on a state of a load connected with the overhead power line.
Therefore, when the overhead power line voltage exceeds a predetermined value, a conventional drive controller for the electric car determines that the car is going through the power failure section (see, for example, Patent Document 1).
Patent Document 1: JP 2002-95299 A